The present invention relates to positioning heads for cutting and marking apparatus, and more particularly the invention relates to a positioning head which is designed so that after the positioning head has been put in place, the positioning head can be locked in place even any other positioning head is being moved for positioning purposes.
Cutting and marking apparatus are known in the art by which creases and cuts are made continuously in a long sheet material, such as, a corrugated board sheet or synthetic resin sheet in the lengthwise direction thereof and this type of known cutting and marking apparatus is so designed that each of the cutter and marking-off wheels is moved into place by a robot arm and then the cutter wheel or the marking-off wheel is locked in place by forcing a liquid such as machine oil into a hollow shaft holding the cutter or marking-off wheel so as to expand and cause the shaft to lock the wheel in place.
However, this type of known apparatus is disadvantageous in that unless the hollow shafts are machined to obtain the desired wall thickness with a high degree of accuracy, the hollow shaft will be expanded non-uniformly and it will thus be difficult to positively lock all the cutter wheels or the marking-off wheels in place.
For this reason, an apparatus has been developed in which each of the cutter wheels as well as the marking-off wheels is engaged with a key so as to fasten the cutter wheel or the marking-off wheel to a shaft, and this apparatus has disadvantages in that the apparatus is complicate in construction and high in cost.
Another type of apparatus is known in the art in which the bosses of all cutter or marking-off wheels are mounted threadedly on a feed screw shaft and the feed screw shaft is rotated to move the cutter wheels or the marking-off wheels into place. A disadvantage of this apparatus is that the rotation of the feed screw shaft results in the simultaneous movement of the adjacent cutter wheels and it is impossible to separately position the cutter wheels. Another disadvantage is that if it is desired to separately position the cutter wheels, it will be necessary to provide for example a feed screw shaft for each of the cutter wheels, making the apparatus complicate and large in construction.